Stay-bolt for boilers.



B. E. D. STAFFORD & E. l. DODDS.

STAY BOLT FOR BOILERS.

APPLICATION FILED NOV. 24. 1914.

1,244,91 5. Patented Oct. 30, 1917.

lxVVENTO/QS UNITED s'mrns rn'rnnr orrron.

BENJAMIN E. D. STAFFORD AND ETHAN I. DODDS, 0F PITTSBURGH, PENNSYLVANIA,

I .ASSIGNORS TO FLANNERY BOLT COMPANY, OF PITTSBURGH, PENNSYLVANIA.

Application filed November 24, 1914. Serial No. 873,793.

To all whom it may concern:

Be it known that we, BENJAMIN E. D. S'rAri-onn and l l'rnnx 1. Donna, citizens of the United States, and residents of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Stay-Bolts for Boilers; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Our invent-ion relates to an improvement in stay bolts for boilers, the object being to provide a yielding coupling for one end of the bolt, whereby the latter will be free to follow the movements of the fire box sheet of the boiler without buckling or unduly straining either of the sheets, thus equalizing the stresses on both sheets.

In the accompanying drawings; Figure 1 is a view partly in section and partly in elevation showing a rigid stay bolt secured to the outer sheet of a fire box; Figs. 2 and 3 are views in section of modified forms.

1 represents a rigid bolt having threaded ends, one of which is secured directly to the inner sheet 2 of the fire box or boiler, and the other to the sleeve or bushing 3 screwed into the outer sheet. This sleeve or bushing 3 is provided with external threads for its attachment to the outer sheet 4; with an angular surface 5 to be engaged by a wrench or other tool employed for attaching it to the sheet 4, and at its outer end with a bore internally threaded to receive the outer end of the bolt. The portionof the sleeve between the externally and internally threaded portions, is formed with -fiutes, convolutions or folds extending circumferentially around the same, which act as a spring which will yield or give under longitudinal or lateral stresses to which the bolt may be subjected.

The sleeve so constructed is heat treated and cooled in oil so that the convoluted, fluted or folded spring section thereof, will retain its elasticity when exposed to the high temperatures to which theyare subjected in use.

By increasing the number of convolutions, flutes or folds 6 and 7, sufficient elasticity may be produced to absorb or take care of all necessary longitudinal and lateral and Specification of Letters Patent.

Patented Oct. 30,1917.

vibratory movements to which the bolt may be subjected. due to the expansion of the bolt itself, or to longitudinal and lateral movement of the bolt due to outward or lateral movement or buckling action of the,

1, except that the bushing is hollowed out closer to the top so as to provide for a. greater number of spring convolutions 0r flutes and the bolt is provided with a telltale bore 11 extending from its outer end inwardly to a point beyond its attachment to the sleeve so as to permit of the escape of steam or water in the event the bolt should be fractured at its point. of attachment to the sleeve, which is the point at which stay bolts usually give way.

In the construction shown in Fig. 3, the bolt, instead of having a threaded head or end, is provided with a rounded or spherical head 8, which is seated on the curved internal seat 9 formed on the sleeve, similar to the Tate flexible stay bolt, and is held thereon by the plug or cap 10 which is screwed into the outer end of the sleeve, the sleeve being provided with a yielding section intermediate its ends, as in the construction previously referred to. With this construction the bolt head is provided with a tell tale bore 11 which extends inwardly beyond the head of the bolt. The inner face of the cap or plug 10 is curved to conform to the outer end of the head 8, and is also provided centrally with a hole 12 for the escape of any steam or water that find its way into the tell-tale 11. The head is normally held into its seat 9 by the cap 10, but the latter is free to be moved outwardly by the outward longitudinal movement of the bolt.

It is evident that many slight changes might be resorted to in the relative arrangement of parts shown and described without departing from the spirit and scope of our invention. Hence we would have it understood that we do not wish to confine ourselves to the exact construction and arrangement of parts shown and described, except as required by the scope of the appended claims.

Having fully described our invention What we claim as new and desire to secure by Letters-Patent, is

1. In stay bolt construction, the combination of a bolt, and a sleeve engaging said bolt and having a yielding or spring section adapted to take the outward end thrust of the bolt.

2, In stay bolt construction, the combination of a bolt, and a sleeve engaging said bolt and having a section adapted to yield in all directions so as to provide for universal movement of the outer end of the bolt.

3. In stay bolt construction, the combination of a sleeve composed of two end sections and an intermediate spring section, and a stay bolt secured to the outer end section.

41A flexible sleeve for stay bolts, comprising a body having one end externally threaded to secure it to aboiler Wall, and

BENJAMIN E. D. STAFFORD. ETHAN I. DODDS.

Witnesses:

EDWIN S. RYon, HOWARD O. COPPEL. 

